The present invention provides a 100% bamboo plank with an interlocking system and associated manufacturing methods. In one embodiment, the 100% bamboo plank comprises first, second, and third layers of 100% bamboo, wherein the layers are laminated together. The layers are independently preconditioned to control moisture content therein. Each layer can be preconditioned by alternately elevating and lowering the moisture content in a plurality of sequential cycles before the layers are laminated together. The middle layer is oriented so its grain is substantially perpendicular to the edges of the plank. The plank had joinery portions formed along the edges, and joinery includes an asymmetric upper joinery member and lower joinery member arrangement for, and at least a portion of the upper joinery member and lower joinery member portions are formed in the second layer.